Carburetor-mounted throttle control



April 9, 1968 R. A. HANSON ET AL 3,376,890

CARBURETORMOUNTED THROTTLE CONTROL Filed April 13, 1966 INVENTORS RUDOLPH A.HANSON 7 JOHN E.F|SCHER ATTORNEYS United States Patent 3,376,890 CARBURETOR-MOUNTED THROTTLE CONTROL Rudolph A. Hanson and John E. Fischer, Jackson, Mich,

assignors to Yard-Man,'Inc., Jackson, Mich, a corporation of Michigan Filed Apr. 13, 1966, Ser. No. 542,347 7 Claims. (Cl. 137-544) The invention pertains to a throttle control for small internal combustion engines, and particularly relates to a throttle control which is directly mounted upon engine carburetor structure.

Small internal combustion engines, such as the type used on lawn mowers, garden equipment, and the like, usually employ a throttle control for regulating the speed at which the engine is to operate. Such throttle controls often .use flexible wires of the Bowden type, whereby the throttle may be operated at a position remote form the engine. For instance, it is common practice with lawn mowers and garden equipment utilizing handles for steering and control purposes that the throttle control lever be mounted upon the handle. Considerable difiiculty has been encountered in assuring proper operation of such remotely controlled throttles, in that the length of the control wire and the added apparatus necessary increases the likelihood of the throttle control malfunctioning due to sticking, kinking or bending of the control wire, or malfunctioning due to corrosion or misalignment of the throttle components.

The present invention pertains to a throttle control for small internal combustion engines wherein the control is in the form of a lever pivotally mounted directly upon carburetor-supported structure. In the practice of the invention, a throttle lever is rotatably mounted upon a carburetor air inlet bushing and the throttle lever is maintained on the carburetor inlet bushing by means of an air filter afiixed to the inlet. The improved throttle control can be adapted to existing engines merely by employing a specially formed bushing which is mounted upon the carburetor inlet, and no modification to the engine components is necessary.

It is, therefore, a basic object of the invention to provide a simplified throttle control arrangement which may be employed with certain types of internal combustion engines which may be readily mounted upon the engine and does not require modification thereto.

Another object of the invention is to provide a throttle control for small internal combustion engines which is very economical to manufacture and assemble, and which is practically foolproof in operation.

Another object of the invention is to provide a throttle control for internal combustion engines wherein the throttle control consists of a lever pivotally mounted upon conventional carburetor air inlet structure and wherein only a specially formed air inlet bushing is required to adapt the throttle control of the invention to existing engines.

These and other objects of the invention arising from the details and relationships of the components of an embodiment thereof will be apparent from the following description and accompanying drawings wherein:

FIG. 1 is a side, elevational view of an internal combustion engine carburetor, gas tank and air filter assembly employing the throttle control of the invention,

FIG. 2 is a plan, detail view of the throttle control in accord with the invention with the air filter removed,

FIG. 3 is a detail, elevational, sectional view as taken along section III-III of FIG. 2, with the air filter in place,

FIG. 4 is a plan view of FIG. 1 illustrating the throttle 3,376,890 Patented Apr. 9, 1968 control lever in a run position in full lines, and showing the throttle control in the stop position in dotted lines, and

FIG. 5 is an enlarged, elevational, sectional view of the bushing employed in the practice of the invention.

The throttle control of the invention finds particular use with small internal combustion engines wherein the carburetor is directly mounted upon the top of a fuel tank. As shown in FIG. 1, the engine is indicated at 10, and a horizontally disposed, elongated carburetor 12 is afiixed to the engine by bolts or screws 14. A fuel tank 16 is attached to the carburetor and extends therebelow, and fuel inlet means extend from the carburetor into the fuel tank whereby a complete carburetor arrangement is produced. An air filter 18 is mounted upon the air inlet of the carburetor, as will be later described in greater detail. This type of engine and carburetor arrangement is manufactured in considerable quantity by the Briggs & Stratton Corporation of Milwaukee, Wis., and is used in horizontally disposed crankshaft engines as well as vertical crankshaft engines such as those used with rotary lawn mowers.

The carburetor 12 includes a lever 20 pivotally mounted thereon which, through suitable linkages, is connected to a governor and a butterfly valve operating shaft 22. Automatic choking mechanism is also, preferably, associated with the lever 20 whereby movement of the lever 20 to an extreme counterclockwise position, FIG. 1, restricts the carburetor air inlet passage to choke the engine for starting purposes. The aforedescribed structure is conventional with a number of models of Briggs & Stratton engines such as model 80906, type No. 945274.

The carburetor 12 includes an air inlet 24 of a tubular form which extends vertically upward, FIG. 3. The air inlet 24 defines an air passage 26 which communicates with the interior of the carburetor through a rectangular orifice 28, FIG. 2, which may be closed by the choke mechanism. The exterior of the carburetor air inlet 24 is formed with several cylindrical surfaces 30 and 32 which cooperate with the bushing mounted upon the air inlet. The exterior configuration of the inlet also includes several radial projections 34, FIG. 3, which prevent the associated bushing from rotating on the air inlet, as will be later described.

The annular bushing 36, which is mounted upon the upper end of the carburetor air inlet 24, is shown in detail in FIG. 5. This bushing is of an annular form and, preferably, is formed of a synthetic, plastic material such as nylon or Delrin which is capable of withstanding the heat and vibration to which it will be subjected. The bushing 36 includes an enlarged diametrical side wall portion 38 whichi 8 adapted to fit over the cylindrical inlet surfaces 30 and 32 and is complementarily shaped with cylindrical surfaces 40 and 42 for cooperation with surfaces 30 and 3-2, respectively. Notches 44 are defined in the side wall portion 38 for cooperation with radial projections defined on the inlet 24, such as that shown in FIG. 3 at 34, whereby the bushing will be keyed to the air inlet for preventing relative rotation between the bushing and air inlet. Exteriorly the bushing 36 is provided with a cylindrical surface 46 concentrically related to the bushing axis. An axially extending bushing portion 48 is also concentrically related to the axis of the bushing and is, preferably, of a cylindrical configuration.

A radially extending shoulder 50 is defined adjacent the cylindrical surface 46 and is disposed nearest the air inlet when the bushing is mounted thereon, as shown in FIG. 3. A radially disposed shoulder 52 is also interposed between the cylindrical surface 46 and the axially extending portion 48.

The bushing 36 is adapted to be firmly mounted on the J upper end of the air inlet 24, wherein the projections 34 of the inlet are received within the bushing notches 44 and surfaces 30 and 40, and 32 and 42 engage.

The throttle control in accord with the invention is, preferably, formed of sheet metal, for instance, such as 14 gauge steel having a thickness of .0747 inch. The throttle control lever 54 includes a primary body portions 56, FIG. 2, having a cylindrical opening 58 defined therein which is adapted to be placed upon the bushing 36 about the cylindrical bearing surface 46, and which will rest upon the shoulder 50. Thus, it will be appreciated that the lever 54 is mounted on the carburetor air inlet 24 for rotation about the axis of the inlet. The control lever includes an upstanding portion 60 which is bent at portion 62 at its upper end to receive a plastic knob 64. A portion of the control lever portion 62 is lanced and bent in the opposite direction with respect to portion 62, whereby a pointer 66 is formed and extends toward the axis of the air inlet, FIGS. 1 and 2.

The throttle control lever body portion 56 includes a portion 68 extending therefrom having a downwardly depending throttle linkage anchor 70 defined thereon. The anchor 70 includes a hole, or holes, whereby a throttle linkage 72 may interconnect the anchor 70 and the carburetor lever 20.

The air filter 18 is mounted on the carburetor air inlet 24 for the purpose of filtering all the air which enters the inlet and prevents foreign matter from being drawn into the carburetor and engine. The air filter includes a cupshaped housing 74 having a side wall 76 and a bottom wall 78. An open cell foam material 80 is located within the housing 74 and, preferably, is moistened with oil in order to retain foreign matter drawn therethrough before it is drawn into the engine. A cover 82 seals the upper portion of the air filter and sufficient clearance is provided between the air filter cover and housing side Wall to define a peripheral opening 84 through which air is drawn into the foam, as well as through holes formed in the bottom wall 78.

A screw 86 extending through the filter cover threads into a threaded bore defined in a projection 88 formed within the carburetor air inlet, and tightening of the screw firmly holds the air filter apparatus upon the carburetor air inlet.

As will be apparent from FIG. 3, the air filter bottom wall 78 is provided with an opening adapted to closely receive the bushing axially extending portion 48, whereby the bottom wall 78 rests upon the bushing shoulder 52. The axial dimension of the cylindrical shoulder 46, when using a control lever formed of 14 gauge material is, preferably, .085 inch and, therefore, it will be appreciated that the thickness of the lever body portion 56 adjacent the opening 58 in the axial direction of the opening is slightly less than the axial dimension of the bushing hearing surface 46. Thus, assembling the air filter 18 on the bushing 36 and firmly tightening the screw 86 will retain the lever 54 on the bushing bearing surface 46 and prevent axial movement of the lever with respect to the air inlet. However, the dimensional relationship between the thickness of the lever and the axial dimension of the bushing bearing surface 46 does not cause the filter bottom surface to bind on the throttle control lever and, thus, free rotation of the throttle control lever 54 on the bushing 36 is assured.

The throttle control lever portion 60 extends upwardly a distance substantially corresponding to the vertical dimension of the air filter, whereby the pointer 66 will be disposed slightly above the air filter cover 82. Indicia are mounted on the air filter cover, as shown in FIG. 4, indicating selected positions of the throttle control lever. For instance, when the control lever is positioned as shown in full lines in FIG. 4, the throttle will be substantially full open. When it is desired to slow the engine, the control lever is pivoted in a counterclockwise direction, FIG. 4, toward the idle position. Stopping of the engine is ac complished by moving the throttle lever to the dotted line position of FIG. 4 wherein the throttle butterfly valve is fully closed and the ignition shorting means 90, FIG. 1, is actuated by lever 20.

In that the control lever 54 is pivotally mounted at a location adjacent the other carburetor control components, malfunctioning due to excessive lengths of linkages or control wires is eliminated. Directly mounting the control lever on the bushing 36, which is in turn mounted on the air inlet, eliminates the necessity for special supporting means and only requires that the bushing be specially formed. The throttle control does not interfere with removal of the air filter mechanism for periodic cleaning, and the locating of the throttle control adjacent the air filter permits the throttle control to be readily accessible for actuation by the operator. The absence of lengthy control wires and linkages eliminates any false readings between the position indicated by the pointer 66 and the actual throttle condition. As the control lever is formed from a simple stamping and as the bushing 36 may be inexpensively molded, manufacture of a throttle control in accord with the invention is economically provided.

It will be appreciated that various modifications to the invention may be apparent to those skilled in the art without departing from the spirit and scope thereof, and it is intended that the invention be defined only by the scope of the following claims.

We claim:

1. A throttle control for an internal combustion engine comprising, in combination, an engine carburetor having a tubular air inlet having an axis, a lever having a handle portion defined thereon and a throttle link anchor defined on said lever adapted to be connected to an engine throttle link, an opening defined in said lever, said carburetor inlet extending through said opening whereby said lever is pivotally mounted on said carburetor inlet for rotation thereabout, and means restraining said lever against axial movement relative to said inlet.

2. In a throttle control as in claim 1 wherein an annular bushing is mounted upon said carburetor inlet circumscribing said inlet, a cylindrical axially extending bearing surface defined on said bushing, said lever opening being circular and rotatably received on said bearing surface whereby said lever rotates about the axis of said bearing surface.

3. In a throttle control as in claim 2 wherein cooperating keying means are defined on said bushing and said carburetor inlet preventing relative rotation between said bushing and inlet.

4. In a throttle control as in claim 2 wherein said bushing is formed of a synthetic, plastic material.

5. In a throttle control as in claim 1 wherein an annular bushing is mounted on said carburetor inlet having an axis coincident with said inlet axis, a cylindrical bearing surface defined on said bushing concentric to the axis thereof and of an axial dimension slightly greater than the thickness of said lever adjacent said opening and in the axial direction thereof, an axially extending surface defined on said bushing, said axially extending surface having a transverse dimension less than said bearing surface and disposed adjacent a free end of said bushing, said lever opening being circular and circumscribing said bearing surface whereby said lever is rotatably mounted on said bushing bearing surface, a first radial shoulder defined on said bushing adjacent said bearing surface axially spaced toward said inlet with respect to said bearing surface, a second radial shoulder defined on said bushing intermediate said bearing surface and said axially extending surface, an air filter housing mounted on said bushing axially extending surface, means maintaining said air filter housing upon said axially extending surface, said filter housing engaging said second radial shoulder and radially extending beyond said bearing surface comprising said means restraining said lever against axial movement relative to said inlet.

6. In a throttle control as in claim 5, cooperating keying means defined on said bushing and said carburetor inlet preventing relative rotation between said bushing and inlet.

7. In a throttle control as in claim 5 wherein said air filter housing includes a side Wall and a cover, throttle position indicia formed on said filter housing cover, said lever handle portion extending adjacent said housing side wall and a pointer defined on said handle portion adapted to associate with said indicia at selected tions of said lever upon said bushing.

References Cited UNITED STATES PATENTS HENRY T. KLINKSIEK, Primary Examiner.

rotational posi- 

1. A THROTTLE CONTROL FOR AN INTERNAL COMBUSTION ENGINE COMPRISING, IN COMBINATION, AN ENGINE CARBURETOR HAVING A TUBULAR AIR INLET HAVING AN AXIS, A LEVER HAVING A HANDLE PORTION DEFINED THEREON AND A THROTTLE LINK ANCHOR DEFINED ON SAID LEVER ADAPTED TO BE CONNECTED TO AN ENGINE THROTTLE LINK, AN OPENING DEFINED IN SAID LEVER, SAID CARBURETOR INLET EXTENDING THROUGH SAID OPENING WHEREBY SAID LEVER IS PIVOTALLY MOUNTED ON SAID CARBURETOR INLET FOR ROTATION THEREABOUT, AND MEANS RESTRAINING SAID LEVER AGAINST AXIAL MOVEMENT RELATIVE TO SAID INLET. 